<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div>
        &lt;script&nbsp;type=&quot;text/javascript&quot;&gt;<br>
	alert(typeof 12345);		//输出number <br>
	alert(typeof &quot;abc&quot;);		//输出string <br>
	alert(typeof document);		//输出object
&lt;/script&gt;
    </div>
</body>
</html>
<script>
    window.onload=function(){
        alert('typeof 12345'+'➡➡' +typeof 12345 +  '\n typeof abc' +'➡➡' +typeof 'abc' +'\n typeof document' +'➡➡' +typeof document )
    }
</script>
<style>
    	body,div {margin:0;padding:0;}
		div {margin:10px;border:1px dashed black;background:white;padding:10px;}
</style>